Security Vulnerability in Linux Kernel Affecting zcrypt in s390 Architecture

CVE-2026-80544

What is CVE-2026-80544?

A security vulnerability exists in the Linux kernel related to the handling of EP11 CPRB domain parsing within the zcrypt component. The issue arises due to the use of struct overlays in the zcrypt_msgtype6_send_ep11_cprb() function, which leads to concerns about maintainability and security. The existing approach assumes a fixed payload structure without validating the actual ASN.1 encoding, making it prone to errors. Furthermore, the logic used for detecting complex length formats lacks proper bounds validation at each parsing step. This vulnerability allows direct access to struct members, bypassing necessary ASN.1 validations. The resolution involves replacing struct overlays with robust ASN.1 parsing techniques that ensure rigorous validation of each field, including payload and function tags with correct bounds checking.

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